This is a note to let you know that I have just added a patch titled

    MIPS: Fix kernel lockup or crash after CPU offline/online

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt17.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 69a9d9c5b02f2e5f01fd93d21f22ffa069f42ddd Mon Sep 17 00:00:00 2001
From: Hemmo Nieminen <[email protected]>
Date: Thu, 15 Jan 2015 23:01:59 +0200
Subject: MIPS: Fix kernel lockup or crash after CPU offline/online

commit c7754e75100ed5e3068ac5085747f2bfc386c8d6 upstream.

As printk() invocation can cause e.g. a TLB miss, printk() cannot be
called before the exception handlers have been properly initialized.
This can happen e.g. when netconsole has been loaded as a kernel module
and the TLB table has been cleared when a CPU was offline.

Call cpu_report() in start_secondary() only after the exception handlers
have been initialized to fix this.

Without the patch the kernel will randomly either lockup or crash
after a CPU is onlined and the console driver is a module.

Signed-off-by: Hemmo Nieminen <[email protected]>
Signed-off-by: Aaro Koskinen <[email protected]>
Cc: David Daney <[email protected]>
Cc: [email protected]
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/8953/
Signed-off-by: Ralf Baechle <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
---
 arch/mips/kernel/smp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index 0a022ee..18ed112 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -109,10 +109,10 @@ asmlinkage void start_secondary(void)
        else
 #endif /* CONFIG_MIPS_MT_SMTC */
        cpu_probe();
-       cpu_report();
        per_cpu_trap_init(false);
        mips_clockevent_init();
        mp_ops->init_secondary();
+       cpu_report();

        /*
         * XXX parity protection should be folded in here when it's converted
--
1.9.1

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